A method and a device for warning a pedestrian of approaching vehicles are described in German document German Published Patent Appln. No. 2010 001 869. In this connection, the device includes a receiving device for electromagnetic radiation, an electromagnetic signal being received, using the receiving device, which is emitted by a vehicle from which a danger of collision may originate. When a threatening danger of collision is detected, the pedestrian is warned of the threatening collision, using a warning signal which is emitted by a warning apparatus mounted in the device.